Dome structures, and particularly building structures employing geodesic dome arrangements, have many and well known advantages, including pleasing appearance, a large ratio of enclosed volume to enclosing surface and, especially for geodesic constructions, a large strength to weight ratio. Such structures have a high degree of stability and are capable of withstanding large stresses including high wind velocities. Yet the construction of such dome structures is expensive, difficult and time consuming. Complex and costly devices for connecting numbers of intersecting struts or panels are frequently employed, as described in the U.S. patents to Fuller, U.S. Pat. Nos. 2,682,235 and 3,197,927.
Many arrangements have been devised to form geodesic structures or dome structures from simple, planar structural elements to facilitate production of the units and to facilitate assembly into a completed structure. A number of attempts have been made to fabricate a dome structure from combinations of hexagonal and pentagonal structural units. However, because of the geometry of a sphere, it is not possible to fabricate or even approximately fabricate a sphere or part spherical structure of identical and regular hexagons.
Where simple structural units are employed in the dome fabrication, the assembly of such units is complex, difficult and time consuming, and may require complex connector elements, as in the patents to Fuller identified above, or in the patent to Emmerich, U.S. Pat. No. 3,341,989.
Efforts to build such structures of hexagons and pentagons have previously required several different shapes, different sizes, or different orientations of the elements. Thus, the patent to Langner U.S. Pat. No. 3,696,566 employs a plurality of preformed, rigid, irregular hexagons so that these hexagons can be selectively positioned in only one orientation in the course of construction.
In the patent to Martin U.S. Pat. No. 3,881,284, like the Langner patent, the dome is divided into predetermined hexagonal and pentagonal areas. However, Martin not only uses rigid irregular hexagons as in Langer, but also requires several different sizes of hexagons. Thus, not only must the structural units of Martin be precisely oriented during assembly but they must be positioned in the proper area of the finished structure. Further, it is more costly to fabricate units of many different sizes and shapes than to make a like number of identical units.
Devices of the prior art do not readily lend themselves to inexpensive and rapid mass production because of the different numbers of complex and diverse structural elements and the complexity of assembly of the structure.
Accordingly, it is an object of the present invention to provide a dome structure and a method for fabrication thereof that eliminates or minimizes above-mentioned problems.